Muffler manufacturing system



Nov. 25, 1969 G, H, SHAFF ET AL 3,479,725

MUFFLER MANUFACTURING SYSTEM Filed March 17, 1967 A v ,y 75

farm/5x52 United States Patent O U.S. Cl. 29--430 5 Claims ABSTRACT OF THE DISCLOSURE A muler manufacturing method forms a muffler shell at one station, muler tubes at another station, and muffler partitions at still another station. The tubes and partitions are then combined into a skeleton and then the skeleton is inserted into the mufller shell and welded in place.

This invention relates to the method of making automotive exhaust mufllers or the like from sheet steel. y

It is the purpose of this invention to provide a muliler manufacturing arrangement that is well adapted to mass manufacture by automated equipment and procedures.

The invention accomplishes the foregoing and other objects =by dividing the component parts of a muffler into groups of similar parts that may be manufactured on substantially the same equipment. The groups of parts are then fed to an assembly area where they are assembled into a mutller and secured together.

The invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a longitudinal cross section through a typical automotive exhaust muffler that may be manufactured in accordance with the invention; and

FIGURE 2 is a schematic diagram of a muffler manufacturing process embodying the principles of the invention.

The muffler 1 of FIGURE 1 comprises an outer shell 3 which is usually oval in cross section. Opposite ends of the shell 3 are closed by inlet and outlet headers in the form of transverse end walls '5 and 7 respectively which have peripheral flanges that fit inside and are welded to the ends of the shell.

The inside of the shell 3 is divided into a number of separate chambers 9, 11, 13, 15, 17, and 19 by means of transverse walls (acting with the end headers) in the form of partitions 21, 23, 25, 27, and 29 which have peripheral flanges that are Welded to the shell 3. Some of these partitions have holes or necked openings therein to provide communication between adjacent chambers as shown. They also have flanged openings to support the aligned gas inlet tubes 31 and 33, the gas outlet tube 35, and the tuning tube 37. The inlet tube 31 is welded inside and to an inlet bushing 39 that in turn is welded to a anged neck 41 in the inlet header 5 and the outlet tube is welded inside and to ran outlet bushing 43 that is formed in the outlet header 7.

Sections of the tubes are perforated or louvered as shown to allow communication between the insides of the tubes and the chambers through which they pass. Spit chamber shells 45 and 47 formed from complemental halves welded together along a midplane are positioned around louvered areas of tubes 31 and 35 to form high frequency sound attenuation or spit chambers.

It will be seen that the muffler 1 comprises the following groups of parts: (a) shell 3, (b) tubes 31, 33, 35, 37 and bushing 39, (c) spit chamber half shells 45 and 47, (d) partitions 21, 23, 25, 27, and 29, and (e) headers 5 and 7.

The processing layout of FIGURE 2 includes a line or conveyor for carrying a coil 51 of sheet steel to each of three stations 53, 5'5, and 57. Station 53 comprises suitable 3,479,725 Patented Nov. 25, 1969 equipment for cutting, blanking, forming, and connecting sheet steel from a coil 51 into a mufer shell 3 and for moving it on to a shell expanding station 59.

Station 55 comprises three substations 61, 63, and 65. Substation 61 comprises suitable equipment for cutting, perforating, forming, rolling, and connecting sheet steel from a coil 51 into tubes 31, 33, 35, and 37. Substation 63 comprises suitable equipment for cutting, perforating, forming, rolling, and connecting sheet steel from a coil `51 into bushings 39. Substation `65 comprises suitable equipment for cutting, blanking, and forming sheet steel from a coil 51 into the spit chamber shell halves 45 and 47.

Station 57 comprises two substations 67 and 69. Substation 67 comprises suitable equipment for cutting, blanking, piercing, drawing, and forming sheet steel from coil 51 into partitions 21, 23, 25, 27, and 29 while substation 69 is capable of performing similar operations to produce headers 5 and 7.

Each of the stations and substations includes suitable conveyor or moving means for moving the parts downstream toward and preferably on to the rotary assembly station 71. Station 55 includes a rotary subassembly station 55a to receive the parts for loading on to station 71 and for assembling the spit chamber shell halves 45 and 47 together on the tubes 31 and 35.

The rotary station 71 includes suitable fixtures 73 to support the various parts while the tubes, partitions, bushing, and headers are subassembled. The parts are welded together into a skeleton structure exclusive of the outer shell 3 as the station 71 rotates toward shell expanding station 59. At station 59 the shell 3 is loaded onto station 71 and the skeleton of tubes, partitions, spit chamber shells, and end headers positioned inside the shell. The combined shell and internal parts are then transferred to the weld station 75. Station 75 has a pre-chamber 77 and a post chamber 79 and a suitable Welder 81, such as an electron beam, intermediate theserchambers. The headers and partitions are welded to the shell in unit 81 and the completed muiller is then transferred to conveyor 83 for transfer to a desired area.

Modifications may be made in the specific procedures and arrangements of equipment disclosed without departing from the spirit and scope of the invention. It will be recognized that certain parts may be omitted in some mufller structures, such as bushings and spit chamber shells, :and that additional parts to those shown may be added.

We claim:

1. The method of making automotive exhaust muillers or the like which comprises passing sheet metal to a shell forming station and forming a shell at such station, passing sheet metal to a tube forming station and forming gas ow tubes at s-uch station, passing sheet metal to a transverse wall forming station and forming transverse walls at such station, passing the tubes and walls to an assembly station and combining them into a skeleton of parts, passing a shell to such assembly station and inserting said skeleton into the shell, passing the assembled shell and skeleton to Ia welding station and welding the walls to the shell to form a muffler.

2. A method as set forth in claim 1 including forming headers at said Wall forming station, passing the headers to said assembly station and combining them with the tubes into said skeleton, and welding the headers to the shell.

3. A method as set forth in claim 1 including forming said walls at said wall forming stataion in the shape of partitions, passing the partitions to said assembly station and combining them with the tubes into `said skeleton, and Welding the partitions to the shell.

4. A method as set forth in claim 1 including forming ICC said walls at said Wall forming station in the shape of partitions and headers, passing the partitions to said assembly station and combining them with the tubes into said skeleton, and welding the partitions and headers to the shell to form a substantially finished muffler.

5. The method of making automotive exhaust mulers or the like which comprises passing sheet metal to a shell forming station and forming a shell at such station, passing sheet metal to a tube forming station and forming gas flow tubes at such station, passing sheet metal to a transverse wall forming station and forming transverse walls at such station, passing the tubes and walls to an assembly station and combining them into a skeleton of parts, inserting said skeleton into the shell, and welding the Walls to the shell to form a mufller.

References Cited Y UNITED STATES PATENTS 1/ 1940 Powell 29l57 1/1945 Buck 29-157 11/1962 Powers etal 29-169.5 10/ 1963 Christman 29-430 10/ 1965 Brown 29-157 3/1966 Selig 29-157 4/1967 Selig 181-48 THOMAS H. EAGER, Primary Examiner U.S. C1. X.R. 

